gis-tools-ts
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A collection of geospatial tools primarily designed for WGS84, Web Mercator, and S2.
141 lines • 4.04 kB
JavaScript
/**
* Fold a number between 0 and 255
* @param n - the number to fold
* @returns - the folded number
*/
export function u8Fold(n) {
return n < 0 ? n + 256 : n > 255 ? n - 256 : n;
}
/**
* Clamp a number between 0 and 255
* @param n - the number to clamp
* @returns - the clamped number
*/
export function u8Clamp(n) {
return n < 0 ? 0 : n > 255 ? 255 : n;
}
/**
* Clamp a number between -128 and 127
* @param n - the number to clamp
* @returns - the clamped number
*/
export function i8Clamp(n) {
return n <= -128 ? -128 : n >= 127 ? 127 : Math.trunc(n);
}
/**
* zero the least significant bit
* @param n - the number to zero
* @returns - the zeroed number
*/
export function u32ZeroBit0(n) {
return n & 0xfffffffe;
}
/**
* Quantize a signed 16-bit number
* @param n - the number to quantize
* @returns - the quantized number
*/
export function i16Quantize(n) {
return n >= 0 ? Math.trunc(n + 0.5) : Math.trunc(n - 0.5);
}
/** A special buffer that stores a 32-bit number and can be converted to different types respecting bit positions */
export class U32I32F32 {
buffer;
view;
/**
* @param value - a 32-bit number
* @param type - the type of the number
*/
constructor(value, type = 'u32') {
this.buffer = new ArrayBuffer(4); // 4 bytes
this.view = new DataView(this.buffer);
this.set(value, type);
}
/**
* @param value - a 32-bit number
* @param type - the type of the number
*/
set(value, type) {
if (type === 'u32')
this.view.setUint32(0, value, true);
else if (type === 'i32')
this.view.setInt32(0, value, true);
else if (type === 'f32')
this.view.setFloat32(0, value, true);
}
/** @returns - the value as an unsigned 32-bit number */
get u32() {
return this.view.getUint32(0, true);
}
/** sets an unsigned 32-bit number */
set u32(value) {
this.view.setUint32(0, value, true);
}
/** @returns - the value as a signed 32-bit number */
get i32() {
return this.view.getInt32(0, true);
}
/** sets a signed 32-bit number */
set i32(value) {
this.view.setInt32(0, value, true);
}
/** @returns - the value as a 32-bit float */
get f32() {
return this.view.getFloat32(0, true);
}
/** sets a 32-bit float */
set f32(value) {
this.view.setFloat32(0, value, true);
}
}
/** A special buffer that stores a 64-bit number and can be converted to different types respecting bit positions */
export class U64I64F64 {
buffer;
view;
/**
* @param value - the value
* @param type - the input type
*/
constructor(value, type = 'u64') {
this.buffer = new ArrayBuffer(8); // 8 bytes
this.view = new DataView(this.buffer);
this.set(value, type);
}
/**
* @param value - the value
* @param type - the input type
*/
set(value, type) {
if (type === 'u64')
this.view.setBigUint64(0, BigInt(value), true);
else if (type === 'i64')
this.view.setBigInt64(0, BigInt(value), true);
else if (type === 'f64')
this.view.setFloat64(0, Number(value), true);
}
/** @returns - the value as an unsigned 64-bit number */
get u64() {
return this.view.getBigUint64(0, true);
}
/** sets an unsigned 64-bit number */
set u64(value) {
this.view.setBigUint64(0, BigInt(value), true);
}
/** @returns - the value as a signed 64-bit number */
get i64() {
return this.view.getBigInt64(0, true);
}
/** sets a signed 64-bit number */
set i64(value) {
this.view.setBigInt64(0, BigInt(value), true);
}
/** @returns - the value as a 64-bit float */
get f64() {
return this.view.getFloat64(0, true);
}
/** sets a 64-bit float */
set f64(value) {
this.view.setFloat64(0, Number(value), true);
}
}
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